Multi-stage depressed collector for small orbit gyrotrons

- University of Maryland

A multi-stage depressed collector for receiving energy from a small orbit gyrating electron beam employs a plurality of electrodes at different potentials for sorting the individual electrons on the basis of their total energy level. Magnetic field generating coils, for producing magnetic fields and magnetic iron for magnetic field shaping produce adiabatic and controlled non-adiabatic transitions of the incident electron beam to further facilitate the sorting.

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Claims

1. A multi-stage depressed collector for connection to a microwave device generating a small orbit gyrating electron beam comprised of individual electrons having varying levels of total energy, said electrons gyrating in small orbits with respect to the total beam radius and traversing into the collector where energy is recovered from the electron beam, said collector comprising:

means for sorting the individual electrons on the basis of their total energy level, including a plurality of stages, each stage including an electrode operative when energized at different voltage potentials for producing electric fields, magnetic iron for magnetic field shaping, and magnetic field generating coils, for producing, when energized, magnetic fields, the electric and magnetic fields being configured so as to direct electrons of the highest energy to the electrode with the greatest negative potential, the electrons with the lowest energy to the electrode with the least negative potential, and electrons with intermediate energies to electrodes with intermediate voltages to maximize energy recovery, the magnetic iron affecting the magnetic fields so as to produce adiabatic and controlled non-adiabatic transitions of the incident electron beam to further facilitate the sorting.

2. The collector of claim 1 including insulating ceramics for separating the collector stages.

3. The collector of claim 1 wherein the collector stages comprise coaxial electrodes and the magnetic iron comprises coaxial magnetic pole pieces.

4. The collector of claim 3 wherein the electrodes enclose portions of the pole pieces confronting the beam.

5. The collector of claim 3 wherein the pole pieces are formed with a gap allowing the electrodes to be insulated from each other.

6. The collector of claim 5 wherein the pole pieces comprise annular rings of magnetic material facing each other across the gap.

7. The collector of claim 1 wherein the collector stages and magnetic pole pieces and coil currents are shaped for generating an electric magnetic field profile for reducing transmission of electrons back toward the incoming beam.

8. The collector of claim 1 wherein one electrode forms a body portion at a potential above ground and remaining electrodes are located therein and are at depressed potentials relative thereto.

9. The collector of claim 1 wherein the microwave device has a tube body section at a potential above ground and the collector is at ground potential.

10. The collector of claim 1 comprising first and second stages, said first stage being at ground potential and surrounding the second stage being at a lower potential.

11. The collector of claim 1 wherein said electrodes comprise a first electrode; a second electrode and a third electrode surrounded by the first electrode; the first electrode and the third electrode having electric potential less than the electric potential of the second electrode.

12. The collector of claim 11 in which the electric potential of the first electrode has an electric potential less than or equal to the third electrode.

13. The collector of claim 12 wherein each stage has a radius and in which the insulating ceramics comprise annular members of selected radii less than the radius of the stages.

14. The collector of claim 1 wherein the stages comprise electrodes and insulating ceramics electrically separating the electrodes.

15. The collector of claim 1 wherein the electrodes comprise coaxially disposed first, second and third electrodes and in which the third electrode comprises an outer portion extending towards the first electrode, an inner portion extending towards the second electrode, and an intermediate portion between the inner and outer portions forming an end wall of the collector.

16. A depressed collector for a small orbit gyrotron generating a beam of electrons having varying energies, said beam centrally located about an axis of the collector for recovering energy therefrom, comprising means for receiving the individual electrons in accordance with their respective energies comprising a plurality of stages, said stages being arranged so that electrons with the lowest energy impinge on a first stage closest to the beam radially outwardly thereof; electrons of a next higher energy impinging on a second stage located centrally of the beam; and electrons of yet higher energy impinging on a third stage downstream of the first and second stages;

magnetic field generating means for producing a magnetic field when energized;
each of said plurality of stages including an electrode for producing, when energized, an electric field; and
magnetic pole pieces for altering magnetic fields produced in the collector to result in the impingement of electrons according to their respective energies.

17. A multi-stage collector for connection to a device generating a small orbit gyrating beam of electrons having varying energy levels, said beam disposed about a common axis, and for recovering energy from the electron beam comprising:

a housing having an inlet for the beam disposed on the central axis, said housing being symmetrical with respect thereto; and
means for attracting electrons in accordance with their respective energies comprising a first, second and third electrodes, electrons having the lowest energy being collected at the first electrode proximate the inlet, and radially outward of the beam, electrons of a next lower level of energy being collected by the second electrode located on the axis radially inwardly of the beam and electrons of a highest energy collected by the third electrode downstream of the first and second electrodes, said electrodes being energized to respective potentials increasing in a negative direction from the first through second and third electrodes; and
magnetic means for producing adiabatic and controlled non-adiabatic magnetic fields to cause the electrons to be further attracted to the electrodes in accordance with their respective energies.

18. The collector of claim 17 wherein the first electrode comprises an annular conical element extending outwardly from proximate the inlet and rearwardly of the housing, and having a first corresponding potential.

19. The collector of claim 18 wherein the second electrode comprises a rounded conical tip facing the inlet and lying on an axis of the housing and being recessed downstream from the inlet and the first electrode and having a potential lower than the potential of the first electrode.

20. The collector of claim 19 wherein a third electrode extends between the first and second electrodes transverse of the axis remote and downstream thereof and having a potential lower than the potentials of said first and second electrodes.

21. A collector for connection to a micro-device generating small orbit gyrating electron beam of individual electrons having varying levels of energy, said electron beam locating about a common axis of said collector for recovering energy of said electron beam, comprising:

a housing having an inlet for receiving the beam;
means for sorting individual electrons of said beam on the basis of their respective energies comprising a plurality of stages with said individual electrons having lowest energy being collected at one of said stages closest the inlet and said individual electrons having lesser amounts of energy being collected at respective ones of said stages relatively more remote from the inlet and wherein each of said stages comprises an electrode having a respective negative potential applied thereto, the first one of the electrode stages having applied the lowest negative potential with respect to the microwave device and subsequent electrodes respectively having applied thereto increasing relative potential; and
means for producing areas of adiabatic and non-adiabatic magnetic fields.
Referenced Cited
U.S. Patent Documents
3153743 October 1964 Meyerer
3368102 February 1968 Saharian
3368104 February 1968 McCullough
3394282 July 1968 Schmidt
3450930 June 1969 Lien
3644778 February 1972 Mihran et al.
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3824425 July 1974 Rawls, Jr.
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Foreign Patent Documents
53-124057 October 1978 JPX
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Other references
  • Gross et al., "Method of Controlling Secondary Electrons For Minimization of Intermodulation in a TWT", Western Electric Technical Digest, No. 45, pp. 17-18, Jan. 1977.
Patent History
Patent number: 5780970
Type: Grant
Filed: Oct 28, 1996
Date of Patent: Jul 14, 1998
Assignees: University of Maryland (College Park, MD), Calabazas Creek Research Center, Inc. (Saratoga, CA)
Inventors: Amarjit Singh (Greenbelt, MD), R. Lawrence Ives (Saratoga, CA), Richard V. Schumacher (Campbell, CA), Yosuke M. Mizuhara (Palo Alto, CA)
Primary Examiner: Robert J. Pascal
Assistant Examiner: Justin P. Bettendorf
Law Firm: Watson Cole Grindle Watson, P.L.L.C.
Application Number: 8/740,108
Classifications
Current U.S. Class: 315/538
International Classification: H01J 23027;